Safety device for a firearm



April 24, 1956 H. A. ASBY, JR

SAFETY DEVICE FOR A FIREARM 2 Sheets-Sheet 1 Original Filed Oct. 24. 1947 MUM. WW

April 24, 1956 H. A. ASBY, JR 2,742,727

SAFETY DEVICE FOR A FIREARM Original Filed Oct. 24, 1947 2 Sheets-Sheet 2 Fig. 3-

gwwwwfo'o States SAFETY DEVICE FOR A FIREARM Harry A. Asby, Jr., Grosse Pointe, Mich.

Original application October 24, 1947, Serial No. 781,869, now Patent No. 2,667,817, dated February 2, 1954. Divided and this application March 27, E53, Serial No.367,917

3 Claims. (Cl. 42-70) (Granted under Title 35, U. S. Code (1952), see. 266) tent light submachine type and more particularly to improved means for simultaneously blocking the firing movement of a trigger and the charging movement of a bolt.

It is an object of this invention to provide a simple and reliable device for blocking the firing movement of the trigger in a firearm whereby the device can be rapidly released to an inoperative position Without the necessity of moving the hand of the operator out of engagement with the trigger.

It is a further object of this invention to provide an improved trigger-blocking device which will also simultaneously cooperate with a retracting handle on the firearm bolt to prevent accidental charging thereof.

A particular object of the present invention resides in providing an automatic firearm with a trigger safety which in the operative position thereof also functions to prevent the entry of dirt or other foreign matter through the cartridge ejection port in the receiver.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. 1 is a side elevational view of the firearm showing the trigger-blocking device of the present invention in the operative position.

Fig. 2 is a fragmentary longitudinal sectional view of the firearm illustrated in Fig. 1 showing the ejection port cover in open position and the bolt in recoiling and cartridge case ejecting position.

Fig. 3 is a view similar to Fig. 2 showing the bolt in battery position and the ejection port cover in closed position and the trigger locked in safe position.

Fig. 4 is a transverse sectional view taken on line 4-4 of Fig. 3; and

Fig. 5 is a top plan view of the ejection port cover.

The firearm to which the invention is applicable is recoil operated, and is positively locked at the moment of discharge of the cartridge. The barrel and barrel extension of such firearm are slidably contained within a tubular receiver and such members recoil approximately %of an inch upon discharge of a cartridge to elfect unlocking of the bolt from the barrel extension. The residual gas pressure then forces the bolt to the end of its recoil stroke whereupon a recoil spring returns the bolt to battery position. A cam member adjacent the rear of the bolt efiects rotation of such bolt to the locked position. A cover is provided on the firearm to shield against the entry of dirt into the breech mechanism when such firearm is not being fired. Means on such cover is utilized to block the fire control mechanism so that the firearm can not be discharged unless such cover is opened.

There is shown in Fig. 3 in assembled relation a portion of a firearm of the automatic type. Such firearm comprises a tubular receiver 1 containing the major elements of the firearm namely, a barrel 2, a barrel extension 3, and a bolt 4. A trigger guard housing 5 is secured to the underside of the firearm in a manner as will be described, such housing containing the fire control mechanism. A magazine well 6 is secured to the underside of receiver 1 immediately ahead of trigger guard housing 5 and is adapted to receive a cartridge magazine 7.

Receiver 1 is a long tubular member and is provided to house the breech elements of the firearm as mentioned above.

Barrel extension 3 (Figs. 2, 3, and 4) is a cylindrical member and is provided with an axial bore 9 .and the forward end thereof is counterbored and threads 10 are provided therein. A cartridge ejection port 101 is provided on top of receiver 1 to permit the fired cartridge cases to be ejected therethrough. An opening 12 is provided on the underside of barrel extension 3 in alignment with magazine well 6 in order that a cartridge may be fed from magazine 7 into the barrel chamber. A transverse notch 13 is provided in barrel extension 3 at the rear end of a cartridge case exit 11 therein to admit a bolt handle as will be later explained. Such notch is formed on a suitable helix and a locking surface 14 is thereby provided against which the bolt 4 is locked as will be later described. A longitudinally disposed spline 15 is provided on the inside'ot barrel extension 3 to permit entry of an extractor 41.

Barrel extension 3 is secured to barrel 2 by threads 10 and such assembly is slidably contained within receiver l for limited longitudinal reciprocal movement therein.

Bolt 4 (Figs. 2, 3 and 4) is a cylindrical member provided with an enlarged diameter rear end portion 26. An axial hole 33 is provided in bolt 4 which is of suitable configuration to receive a firing pin 34. An enlarged head portion 35 is provided on firing pin 34 which is contained within a counterbored portion 36 of hole 33. A helical spring 37 surrounds firing pin 34 and such spring abuts the head 35 of firing pin 34 and the bottom of counterbored portion 36, such spring being provided to bias firing pin 34 rearwardly so that the point thereof can not accidently strike the primer of a cartridge.

The cylindrical body portion of a bolt cam 49, that is slidably contained within receiver 1 adjacent the rear end of bolt 4, is counterbored and one end of a recoil spring 52 is inserted therein. The other end of spring 52 is retained within receiver 1 by a recoil plug 53. Trigger guard housing 5 (Figs. 2 and 3) is of built-up construction and comprises a trigger guard 59, a pistol grip 60 and side plates 61 and 62. These elements are preferably brazed to form a unitary structure.

A hammer 68 (Figs. 2 and 3) of substantially triangular construction is pivotally mounted Within trigger guard housing 5 by a transverse pin 69. A spring biased plunger 70 is arranged as shown in the appended drawings to bias hammer 68 forwardly to strike firing pin 34. A secondary sear notch 71 is provided in the upper rear apex of such hammer.

. A secondary sear 72 is pivotally mounted on a transverse pin 73 somewhat to the rear of hammer 68. Secondary sear 72 is biased forwardly by a spring 74 so that such sear can engage secondary sear notch 71 on hammer 68. An upwardly projecting lug 75 is provided onsecondary sear 72 which projects through a slot 76 provided on the underside of receiver 1 so that such lug lies in the path of the bolt cam 49 for a purpose to be later described. Slot 76 is of sufl'icient length to permit hammer 68 to rotate upwardly into receiver 1 *to strike firing pin 34.

A trigger 77 and a "s'a'fe'tyla't'ch'78 are mounted on a transverse pin 79 in trigger guard 59. Trigger 77 is provided with. an upwardly projecting .lug 80.. Such lug is providedwith a transverse sear notch. 81. A forward- 1y projecting lug 82 on. hammer :68 integrally for-med the ,.-lower apex ,of such ham mer is arranged to .be engaged "by sear notch" 81 when hammer 68 is in the cocked positionv A spring 83 isprovided in back of trigger 77 ,tobias suchtrigger forwardly so that sear notch '81 will, engage hammer 68 upon release of such trigger. A. substantially horizontal lug 84is provided outrigger 7,7 which strikes ;a.jportion 85. of trigger. guard housing} to 'limit the forward pivotal movement. of trigger77. g, I

Safety"latch 78 is a substantially L-shaped member, the QWer portion ofsuch member however'is arcuately formed ,as shown, at 86- and rests within a slot 92 in trigger guard 59'to permitlimited pivotal movement. of latch- 78, A spring. 87 is placed betweenthe arcuately formedportion 86 :of latch'78 and portion 85 ,of trigger guard housing '5. Suchspring -is provided to bias the upright portion .of latch 78. forwardly into engagement with a stud 88 mounted on a cover'89 as will be later described. A forwardly faci'rig lug 90 is providedon latch 78 which rests on a horizontal shelf "91 provided outrigger guard'housing to'limit the forward movementjof the upright portion of latch 78. 4

A'vertic'ally disposed recess 93 'is provided on the underside of trigger guard housings on the forward end thereof. A magazine latch '94 is 'pivotally mounted thereinby a transverse-pin 95-. Such latch comprises a vertical arm 97 and ajhorizontal arm 98 and as spring 96 is'provided in the rear of arm 97 to bias such latch forwardly. The end of arm 9 8 .rests on. top of shelf 91 of portion85 to'secure the "rear, end 'of such'latch thereon.

"An integral projection 99 is provided on'the lower forward face of'latch '94. "Such projection is arranged to engage a corresponding *lug100 provided onmagazine 7 to secure such magazine within magazine well 6. Projection 99 is readily rotated out of-the path of lugl100 by--"-pivotinglatchf94 about pin 95 against the bias 'of spring 96 in a clockwise direction. Thispermits 'rnaga-. zine 7 to 'drop out of magazine well 6. The insertion of a loaded magazine into magazine well 6"carns'projection 99 of-latch 94 out; of the, path'thereoffuntil such projection'is' inback of lug-100, whereupon springl'96 biases latch 94 *in at-"counterclockwise directionso that projection 99 engages lug 100;

Cover 89 is of suitablearcuate shape to surround the ejection port 101 of receiver 1.' Suchcover-is'pivotally secured toreceiver '1- by-ahinge 102. A hinge pm 103 is provided to secure the" cover to hinge 102 and a torsion spring-104 surrounds -pin"103.*- Spring 104 is mounted in such fashion on; pin 103 and --secured' to cover '89; so as to normally maintain such=cover-in the open position. An-'-integral-downwardly"projecting tab 105. is provided near the rear edge of cover 89aand-stud 88 is secured to such-tab preferably by'-a-collar-106. ln the'closed position of cover89 (Fig. 4-),-stud--88 assumes a substantially horizontal position. The inwardly projecting end of stud 88 is-conically shapedas shown at 107 and a transverse slot 108 is providedon stud 88 which is engaged by safety latch 78 as will bepresently described. A notch 109 (Fig. 1) 'is provided in cover 89 to permit such cover to clear a bolt handle 48 when cover 89 is closed. Such notch likewise prevents bolt handle 48 from being retracted .therebyproviding a further safety feature. 7 t

When cover 89is closed against the bias of" spring 104, the .conically shaped and .1-07. of stud 88 contacts the upright arm of -latch.78 thereby rotating such latch slightly ina counterclockwise direction until slot 108' in stud 88 is aligned-with the upright member of latch 78.

Spring 87 then biases the 11 right arm "of latch '78 in to disengage hammer 68 'from sear notch 81 on trigger I 77. Thusthere'is provided a simple and positive method of securing the fire control mechanism in a safe position.

i h I Operation I v The firearm illustratedin the appended drawings is charged by insertingaloaded magazine 7 into niagazine well 6. Magazine latch 9.4 engages lug 100'on-maga'zine 7 to secure such magazineto the .firearm. Cover 89 is released by pushing forwardly on safety latch 78 which rotates the upwardly projecting arm thereof in a' counterclockwise direction and out of slot 108 in stud 8S. Torsion spring 104 then biases cover 89 about hinge 102 to the. openposition, thus uncoveringejection port 101' and removiug 'that portion of cover 89Jsurrounding bolt handle 48. The 'firearrn'rnay now be charged fby retracting bolt handle 43 rearwardly. Manual retraction 'of'bolt'handle '48 moves the breech elementsrearwardly a distance of approximately of an inch. Con: tinued rearward "movement of bolt 4 forces haminer 68 to be rotated in a counterclockwise direction whereupon such hamm'eris engagedby sear'notch 81 of trigger 77. Driving spring "52 returns 'bolt'4 and bolt cam "49 to the"b'at,tery =position upon release of bolt handle 48;

.The'firearm is 'now charged and a cartridge is cham-' bored in the barrel; Release of'harnmer"68 is effected when 'trigger 7'7 is' pulled rearwardly, rotating lug '80 in a clockwise-direction"which "disengages' sear ,notch' '81 then forces hammer68'in a clockwise direction'to strike firing pin 34 whereupon the cartridge is discharged. The

re'coilyforce resulting-from the discharge of the cartridge forces' barrel 2,"barrel extension 3, a'nd'bolt 4 contained within=barrelextension 3,-to move rearwardly approxiof bolt 4"is" direction,- but-a's trigger '77 is stillheld rearwardlygsear 72. Hammer "68 is thus h'eld momentarily int-he cockedposition until bolt 4 is r'eturned to its'locked battery position by sp'ring 52. "Immediately after locking of bolt 4;:bolt cam 4'9 strikes: theupwardly projecting lug 75 ofsecondary sear 72 thereby rotatingsuch sear inaclockwise :direction. Su'chtrotation causes secondary sear-"72 to slip outiof engagement with sear notch 71 on hammer 68; by plunger 70 to strike firing' pin 34. i I

It is= desired-torpointoutithat the fire control mechanismherein described is for full automatieoperation only. Accordingly r such firearm mean only be fired in bursts ofshortzduration' or long continuous bursts. Re lease of trigger 77 at any time during firing iperrnits sear-notch 81rtofire-engage lug-82 of hammer 68 to hold such hammeriin the-cockedposition.

'F-rom the foregoing dcscriptionit is readily apparent that there tis there; provided- 'alight, sturdily constructed firearm that-"is posi'tivesinoperation andone that can be readilyandcheaplyfabricated. This firearmis provided with a positive firecoh-trolmechanism for automatic fire and has positive safety features whereby the trigger is securely-blocked .to 'prevent accidental discharge- 0h the firearm. Eur-ther,-this--firea'nm is positively locked at the moment of dischargeaof a 'cartridge'and' remains so for anappreciable-length: of time to permit safe unlocking at;a substantially-reducedbreech pressure. 1

zIt is. to be understood that' 'the form of my invention,

l 'hushammeri 68 is free to's'bebiased forwardlyherewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of my invention, or the scope of the subjoined claims.

I claim:

1. In a firearm, a receiver having a cartridge case ejection port therein, a cover pivotally secured to the exterior of said receiver in position to close over said ejection port and block entry of foreign matter therein, spring means biasing said cover toward the open position, a pivotal trigger, safety means associated with said cover for blocking firing movement of said trigger when said cover is closed, and latch means engageable with said safetymeans to hold said cover closed.

2. In a firearm, a receiver having a cartridge case ejection port therein, a cover pivotally secured to the exterior of said receiver in position to close over said ejection port and block entry of foreign matter therein, spring means biasing said cover toward the open position, a pivotal trigger, an outwardly projecting stud adjacent the rear end of said cover, said receiver having an opening in the side thereof for passage of said stud therethrough during the closing of said cover, said stud being thereby positioned to block the firing movement of said trigger, a

reciprocable bolt having a charging handle thereon, said cover having a notch adjacent the rear end thereof and engageable with said bolt handle simultaneously with the blocking of said trigger whereby said bolt is locked against charging movement, and a latch having an upwardly projecting arm engageable with said trigger-blocking stud to hold said cover in the closed position.

3. The combination defined in claim 2 including means for pivotally mounting said latch conjointly with said trigger, an upwardly projecting arm on said latch genernliy coextensive with said trigger arm, said latch arm having a beveled forward edge, said stud on said cover terminating in a conically tapered end engageable with said beveled forward edge of said latch arm for camming said latch out of the path of saidstud as said cover is being closed, said stud having a vertical notch therein, and spring means biasing said latch to pivot said arm thereon into engagement with said notch and thereby lock said cover in the closed position, said latch having a downwardly projecting exposed finger portion by means of which said latch is actuated to release said stud whereby said cover is automatically biased to the open position.

No references cited. 

